Artificial stone

Details Artificial stone Artificial stone

2000-09-11

2001-10-30

Thomas, Alexander S. (Department: 1772)

Compositions

Inorganic luminescent compositions with organic...

C252S301260, C252S301210

Reexamination Certificate

active

06309562

ABSTRACT:

TECHNICAL FIELD OF THE INVENTION
The invention of the present application relates to an artificial stone. In further detail, the invention of the present application relates to a luminous artificial stone having light regenerating function or luminous noctilucent function, which exhibits excellent luminance and durability of luminance, useful as building materials, view improving materials and the like; more specifically, for instance, as ornaments visible in night or in dark field environments, e.g., direction indicators, position guides, etc.
BACKGROUND OF THE INVENTION
Artificial stones well known in the art are produced by mixing crushed naturally occurring stones with resin and solidifying the resulting product. Further, various improvements have been made to these artificial stones in order to obtain products having the appearance like a naturally occurring stone such as a marble, a granitic stone, etc., and yet having excellent hardness and strength
As an attempt to improve the function and performance of the artificial stones above, there is proposed to impart alight-emitting function by using a luminescent or fluorescent substance or a light-emitting substance such as a light-storing material. As such attempts, there is proposed a method comprising solidifying a mixture obtained by mixing a phosphorescent substance with a resin component which is used as the binder of an artificial stone, or a method comprising constituting the artificial stone by mixing a light-storing fluorescent substance or an ultraviolet fluorescent substance, e.g., strontium aluminate, with an unsaturated polyester, a methacrylic resin, a glass, etc., and after solidifying the resulting mixture, crushing it to provide aggregates for the artificial stone.
However, the luminescent or fluorescent artificial stones known heretofore obtained by either of the methods above are based on the phosphorescent function of tie light-storing materials and the like, and are yet to be improved in initial brightness or in the durability of the brightness. From the viewpoint of practical disaster prevention, it has been demanded an artificial stone still improved in luminance and having a longer lasting luminance.
In the conventional artificial stones, moreover, the effective phosphorescent function was available only from the exposed surface portions of the resin components or the aggregates, and not from the light-storing materials or the fluorescent substance incorporated inside the molding of the artificial stone. However, a fluorescent substance such as a light-storing material and the like are extremely expensive, and even a small amount of addition of such fluorescent substance greatly increases the product cost of the artificial stone by about three to ten times. Accordingly, such conventional artificial stones produced by internally incorporating the fluorescent substance were costly, and thereby practically unfeasible.
Thus, it has been considered conventionally to provide a light-emitting layer only on the surface portion of the molded artificial stone, or only to the guiding figures or patterns; however, the local allocation of the light-storing material and the like further makes it difficult to improve the brightness and the durability of the brightness. Moreover, since the light-emitting layer of a conventional type is inferior in adhesive strength with the base material and is poor in resistance against abrasion, it has been found to suffer problems of not exhibiting the desired function, particularly when used in floorings, due to the separation, peeling off, wear, etc., of the light-emitting layer.
Accordingly, even in case the light-storing substance is used only for the figures and patterns, there was still a demand of realizing a novel type of artificial stone still excellent in its phosphorescent luminance and durability of the luminance, and yet improved in adhesiveness and integration with the base material of the light-emitting layer and in mechanical properties such as the resistance against abrasion, etc., suitable for use as, for instance, a light guide under a dark field environment or an ornamental material in night time.
DISCLOSURE OF THE INVENTION
In order to solve the problems above, the invention according to the present application provides an artificial stone which comprises, with respect to a total quantity of the product, 82-93 wt. % of inorganic aggregate and 7-18 wt. % of resin as main components, wherein the inorganic aggregate contains at least as a part thereof a luminescent, fluorescent or noctilucent substance and a transparent inorganic aggregate, or a transparent inorganic aggregate with the luminescent, fluorescent or noctilucent substance baked on the surface thereof, and the product further contains 0.5-3.5 wt. % of an organic nitrogen-containing compound with respect to a total quantity of a product being compounded into the molded body.
Furthermore, the present invention provides an artificial stone as described above, wherein the organic nitrogen-containing compound is an amine, preferably a cyclic amine, and more preferably, a cyclic amine containing a carbonyloxy (—CO—O—) group.
The composition of the artificial stone according to the present invention is described first. As the main components, the artificial stone contains an inorganic aggregate and a resin. For the inorganic aggregate usable in the present invention, usable are those selected from a wide range of materials, such as naturally occurring stones, naturally occurring minerals, artificially synthesized inorganic materials, glasses, metals, etc.
The quantity of the inorganic aggregate incorporated into the product accounts for 82 to 93 wt. % of the total amount of the product. On the other hand, the resin accounts for 7 to 18 wt. % with respect to the total quantity of the product. The sum (total) of the both components accounts for less than 99.5 wt. % of the total quantity of the product.
What is most important in the present invention is that, in the light-emitting portion, at least a part of the aforementioned inorganic aggregate contains a light luminescent, fluorescent or noctilucent substance and a transparent inorganic aggregate, or a transparent inorganic aggregate having a surface coating layer comprising a luminescent, fluorescent or noctilucent substance.
In case a transparent inorganic aggregate is incorporated together with the luminescent, fluorescent or noctilucent substance, the weight ratio of these components is in a range of from 1:2 to 1:200, and the total of both accounts for 82 to 93 wt. % of the total composition of the light-emitting portion.
Further, a transparent inorganic aggregate provided with a surface baked coating using the luminescent, fluorescent or noctilucent substance can be incorporated into the light-emitting portion.
The requirements above are first to be defined concerning the mechanical properties such as the resistances against peeling off, dropping off, and abrasion, as well as the phosphorescence with respect to the light-emitting properties.
As the preferable inorganic aggregates, there can be mentioned a combination of the following two types. More specifically, one is the small inorganic particles ranging from 5 to 70 mesh (based on Tyler sieves), i.e., a component consisting of small particles of inorganic materials properly selected from, for instance, a mineral such as a quartzite, an olivine, a feldspar, a mica, etc.; a naturally occurring rock such as a granite, a metamorphic rock, etc.; a china, a glass, a metal, etc.
Furthermore, a component of fine particles passing through a 100-mesh sieve (based on Tyler sieves) is favorably used together with the component of small particles above. As the fine particle component, there can be mentioned, for instance, a fine particle component selected from various types of naturally occurring or artificial materials. More specifically, usable are the readily available fine particle component such as the powders of calcium carbonate, aluminum hydroxide, silicic stones, etc.
As a part of the fine particle

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